Posts that violate the guidelines or Terms and conditions of
Use of the Missing-lynx.com discussion groups will be
erased, and repeated violation of this policy may result in
termination of the violator's account.

I think it depends somewhat on the setting...

As a general rule there is nothing that is absolutly impossible. But if you want to depict a frontline unit in Russia, which has had several refits or even has only been created in 1943 the likeliness is somewhat different then for example you showing the retreat through Czech lands in 1945 where alot of 2nd line units with their older trucks and cars where involved.

In general you will find examples of all the vehicles you mentioned in late war footings, there obviously being the old runners that still soldiered on or had recently been scraped together from training units to bolster the ever dwindling resources of the units.